The present invention relates to an ink jet printer, and in particular, to an ink jet printer employing a longer stationary print head.
As a sort of an ink jet printer, there is known a printer that uses a longer print head. In the printer of this kind, the print head is a stationary head having a length corresponding to the total width of a recording medium, and a document and others are printed by an ink jet on a recording medium that faces the print head and is conveyed in the direction perpendicular to the longitudinal direction of the print head (for example, see Patent Document 1).
The ink jet printer of this kind that prints immediately for the total width of a recording medium by a longer print head can print much faster than the so-called shuttle type printer that prints while sweeping a movable print head along a recording medium.
(Patent Document 1) TOKKAI No. 2003-200563 (page 3, FIGS. 1-2)
Because of a high speed, the printer stated above is suitable for a task to conduct printing a document and others in a relatively large volume. When a printer is used for a printing task, a speedup of the printing speed is required for improvement of efficiency.
Though a speedup of the conveyance speed for a recording medium and conversion to the higher frequency for print head driving that follows the foregoing speedup of the conveyance speed are needed for a speedup of the printing speed, if the frequency for driving the print head is raised, the dispersion of an amount of liquid-drop of ink to be jetted, an angle of fly and of a flying speed grows greater, which increases an error of an impact position of an ink drop and lower a quality, together with a speedup of the conveyance speed for a recording medium. Further, troubles such as quality lowering resulting from changes in physical properties of ink caused by temperature rise in the print head and problems of an ink overflow and contamination on a recording medium caused by problematic fixing and drying of ink.
To use the ink jet printer having such characteristics conveniently as a printer for business use, it is necessary to work out to enhance productivity of printing as high as possible, taking that characteristics into account. Now, an object of the invention is to realize an ink jet printer wherein the trade-off between the printing speed and the print quality is achieved under the condition of satisfactory productivity.